MOM's MENCA brings divine wealth from Mars

MENCA (Mars Exospheric Neutral Composition Analyser) is a quadrupole mass spectrometer on-board India's Mars Orbiter Mission, MOM. In Indian mythology, "Menaka" considered to be the prettiest dancers (nymph)  in "Indralok" the palace of god's god, "The Indra". Hence the first published results of MENCA from Mars is like a divine wealth, I must say. The results are published 2-days ago in Geophysical Research Letters, GRL. Barring few conference abstracts  and a recent summary of MOM sub-systems in an Indian journal, this is the very FIRST science result that the Indian MOM has churned out on the international forum; hoping for many more to come.

A series of posts here have been appearing soon after the MOM project was approved by Indian Central government. In one of my posts here, I had given a highest rank (8 out of 10) to MENCA among the FIVE instruments flown on MOM. Today my prediction has come TRUE; I feel I am on seventh cloud. I could say this not only for the prediction, but also also due to my personal experience of our attempts to publish the peak#18 (Water) data from Moon in December 2008, measured by a similar kind of instrument in the Chandrayaan-I. It was (then) rejected by calling it as "contamination" (Science journal). Later in November-2009 the M3-instrument's remote sensing data of Water from Chandrayaan-I was published by Science.

Credit : SPL, VSSC, ISRO
MENCA is based on the similar platform as that of CHACE (CHandra's Altitudinal Composition Explorer) built at Space Physics Laboratory (almost by the same group) of ISRO's Vikram Sarabhai Space Center, in southern part of India. Thanks to the rule books of ISRO, a heritage class of instruments is always struck to the similar processes of qualifying for the flight; it is only the mission demands which could bring in any minute alteration. Basically, its a neutral gas mass spectrometer covering 1-300 amu range with a capability of separating single mass unit. The Mars Orbiter Mission was inserted into Martian atmosphere in 24th September 2014; with an orbit parameters of 400 X 71,000 km.

After the completion of ONE year of primary mission (Sept. 2015), the present observations were made as MOM is made to dip down to 260-km from its normal perigee point of 400-km. While dipping down, MENCA had better chances of collecting neutral sopecies data.  MENCA has successfully measured the altitudinal profiles of CO2, (N2+CO) and O (details given in the GRL paper). This is exactly what I had recommended in my Nov. 2013 post that to be able to monitor meaningful data with MENCA, the perigee of MOM was needed to be lowered so as to skim through the neutrals.

It gives me an immense satisfaction and PRIDE that MENCA has come up with flying colors and definitely stands to get more than 8-points out of 10, as I had predicted. To repeat from my earlier post, among the five payloads on-board MOM, both 1. MCC, 2.TIRS are imaging instruments. Big science is expected from 3. Methane Sensor for Mars, MSM. The 4. Lyman Alpha Photometer, LAP too carries a great scientific value for its potential in estimating Martian atmospheric loss.  But, the day belongs to 5. MENCA. The hard lessons learned in developing CHACE during Chandrayaan-I were all worth. I like to end by saying " MENCA's triumph on Mars means ...........  Lunar CHACE was correct"

A similar version of this post appeared on Planetary Science site ....

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